The overall objective of the investigation is to determine the stress-strain characteristics of the periodontal ligament and to develop a mathematical model based on his data that is capable of prediction tooth displacement. Laser interferometry is being used to measure minute tooth displacement. The goal for year 02 was to a) calibrate the 10:1 tooth model and b) develop a pulse laser system in preparation for the in vivo studies planned for 03. New techniques of exposing and developing photosensitive plates have been developed for the pulsed system and are presently used with very satisfactory results. In the near future we will be able to make holograms of moving objects by "freezing" them with extremely fast ruby laser bursts. Presently, the attempts are being made to obtain the real image while reconstructing holograms. For this purpose a liquid gate plate holder is used with appropriate optical arrangement. Experimental data from holographic experiments has been obtained and the analysis is being prepared to analyze this area. A correlation between the experimental and the analytical procedures will soon be available. Work will continue toward the following goals: to further develop the pulse-laser system and to calibrate it on the 10:1 tooth model; to apply the pulse-laser system and the piezoelectic transducer to a small animal (rat) in vivo; to collect data of the force-displacement characteristics of the periodontal ligament in vivo; to start the in vivo experiments with a larger animal (monkey).